/scratch0/jsnuveri/BDSIM/BDSIMgit/bdsim/src/BDSRfCavity.cc

#include "BDSGlobalConstants.hh" 

#include "BDSBeamPipeInfo.hh"
#include "BDSRfCavity.hh"
#include "G4Tubs.hh"
#include "G4VisAttributes.hh"
#include "G4LogicalVolume.hh"
#include "G4VPhysicalVolume.hh"
#include "G4UserLimits.hh"

#include "G4MagIntegratorDriver.hh"

#include "G4ExplicitEuler.hh"

class BDSTiltOffset;

BDSRfCavity::BDSRfCavity(G4String           name,
                         G4double           length,
                         G4double           grad,
                         BDSBeamPipeInfo*   beamPipeInfo,
                         BDSMagnetOuterInfo magnetOuterInfo,
                         BDSTiltOffset      tiltOffset):
  BDSMagnet(BDSMagnetType::rfcavity, name, length,
            beamPipeInfo, magnetOuterInfo, tiltOffset),
  itsGrad(grad)
{
  itsEField    = NULL;
  fChordFinder = NULL;
  fStepper     = NULL;
  fIntgrDriver = NULL;
}

void BDSRfCavity::BuildBPFieldAndStepper()
{
  G4int nvar = 8;

  // set up the magnetic field and stepper
  G4ThreeVector Efield(0.,0.,itsGrad * CLHEP::megavolt / CLHEP::m);
  itsEField=new G4UniformElectricField(Efield);

  G4EqMagElectricField* fEquation = new G4EqMagElectricField(itsEField);

  itsBPFieldMgr = new G4FieldManager();
  
  fStepper = new G4ExplicitEuler( fEquation, nvar );
  //itsStepper = new G4ClassicalRK4( fEquation, nvar );

  G4double fMinStep = BDSGlobalConstants::Instance()->GetChordStepMinimum();
 

  itsBPFieldMgr->SetDetectorField(itsEField );

  delete fChordFinder;

  fIntgrDriver = new G4MagInt_Driver(fMinStep,
                                     fStepper,
                                     fStepper->GetNumberOfVariables() );
  
  fChordFinder = new G4ChordFinder(fIntgrDriver);

  fChordFinder->SetDeltaChord(BDSGlobalConstants::Instance()->GetDeltaChord());
  itsBPFieldMgr->SetChordFinder( fChordFinder );
}

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